An HPLC method was developed for the determination of
methylglyoxal in Manuka honey of New Zealand. The honey sample was dissolved in
water and mixed with o-phenylenediamine solution for derivatization.

After the
reaction for at least 8 h in the dark at room temperature, the solution was
filtered with 0.22 microm membrane and injected into an HPLC system for
analysis. The separation was carried out on a Kromasil reversed phase column
with gradient elution. The mobile phases were methanol and 0. 1% (v/v) acetic
acid aqueous solution. The detection wavelength was 318 nm. The external
standard method was used for quantitation. The linear range of methylglyoxal
was 1-50 mg/L with a correlation coefficient of 0. 999 9. The LOD (S/N = 3) and
LOQ (S/N = 10) were 0.02 mg/L and 0.06 mg/L, respectively. The recoveries at
the spiked levels of 50, 100, 200 mg/kg were 98.3%-101.5% and the RSDs (n = 5)
were less than 5%. The derivative of methylglyoxal was stable within 24 h.

The
results showed that the pretreatment of this method is simple and the
sensitivity, the recovery and repeatability are good. This method can be used
for the quality control of Manuka honey of New Zealand, and also for the
detection of methylglyoxal in Chinese honey.